How to Splice Automotive Wires

Use a professional tool and moisture sealant for first-class results.

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Introduction

Use a professional crimper and electrical moisture sealant to make quick, solid connections in auto wiring.

Tools Required

  • Crimper

Materials Required

  • Butt connectors
  • Electrical moisture sealant

Project step-by-step (3)

Step 1

Crimp the Connector

Crimp-on wire connectors work well if they’re crimped properly (a 5/16-in.-wide crimp) and sealed (usually with heat-shrinkable tubing). But most cheap crimping tools only make a 1/8-in. crimp, so you’d have to make four of them for a simple butt connection. Buy a professional crimping tool and a roll of electrical moisture sealant.

Strip the insulation so only the bare wire is inside the connector. Then make a single 5/16-in. crimp on each side of the butt connector.

A person is using pliers to connect wiresTMB Studio

Step 2

Cut the Moisture Sealant

Cut a section of moisture sealant to cover the entire connector and a 1/2-in. overlap on each end.

A person using tape to connect wiresTMB Studio

Step 3

Seal the Splice

Double it over and squeeze it together with your fingertips.

A person using black tape to connect wireTMB Studio